Lignin Incorporation Combined with Electron-Beam Irradiation Improves the Surface Water Resistance of Starch Films

Abstract

We investigated the potential of an electron-beam post-treatment to tailor the properties of 70/30 and 80/20 wt. extruded starch-lignin films. The effect of a 400 kGy radiation on films differing essentially by the kind of lignins incorporated (lignosulfonates/alkali lignins) was assessed both at the macroscopic and the molecular levels. Changes in the polymer molecular structure were studied by IR spectroscopy, by thioacidolysis as well as by model compound experiments. Electron beam-irradiation at 400 kGy, a rather high dose for processing natural polymers, alters to some extent the mechanical resistance of the starch-based materials. However this treatment substantially reduces the hydrophilic surface properties of the films, while not harming their biodegradability. Involved in radical cross-coupling reactions, lignin phenolic compounds are likely to play a primary role in the formation of a hydrophobic condensed network. This study suggests that lower irradiation doses might yield biomaterials with improved usage properties.

Preparation and properties of plasticized starch/multiwalled carbon nanotubes composites

“…The WAXD patterns of the PS/MWCNTs nanocomposites still retained characteristic peaks of pea starch regardless of the MWCNTs content. There is no evidence of any additional peak, such as an extra peak at 2y 5 21.58 ascribed to the accumulation of plasticizers at the interface of whiskers and starch is observed, which was reported by Dufresne et al 18 for glycerol PS based nanocomposites filled with whiskers. Therefore, it can be concluded that there is no transcrystallization in the MWCNTs reinforcing system.…”

“…As we know, the PS plasticized by glycerol exists as a complex heterogeneous system composed of glycerolrich domains dispersed in a starch-rich continuous phase, 44 and each phase should exhibit its own T g . 18 Therefore, the transition at 16.58C of PS should be associated with glass transitions of starch-rich phase. The T g transition of glycerol-rich phase located in the temperature region from 280 to 2508C, unfortunately, cannot be detected because of the low sensitivity of DSC.…”

“…11,12 However, compared to conventional synthetic thermoplastics, biodegradable products based on starch, unfortunately, still exhibit many disadvantages, such as water sensitivity, poor processability, and poor mechanical properties. 13 To solve these problems, various physical or chemical modifications of the starch have been considered, including blending with other synthetic polymers, 14,15 the chemical modification, 16 or graft copolymerization, 17 and incorporating fillers such as lignin, 18 fibers or crystalline, [19][20][21][22] tunicin whiskers, 23,24 and clay. 25 Multiwalled carbon nanotubes (MWCNTs) are stiff macromolecular structures having outer diameters of about 30 nm, and lengths of 1-100 lm.…”

Starch-based nanocomposites reinforced with flax cellulose nanocrystals

“…However, compared with conventional synthetic thermoplastics, biodegradable products based on starch, unfortunately, still exhibit many disadvantages, such as water sensitivity, brittleness, and poor mechanical properties [6]. Vari-ous physical or chemical means have been used to solve these problems, including blending with other synthetic polymers [7][8][9], the chemical modification [10][11][12], graft copolymerisation [13], and incorporating fillers such as lignin [14], clay [15], and multi-walled carbon nanotubes [16]. More recently, there is an increased use of cellulose nanocrystals (CNs) as the loading-bearing constituent in developing new and inexpensive biodegradable materials due to a high aspect ratio, a high bending strength of about 10 GPa, and a high Young's modulus of approximately 150 GPa [17].…”

Preparation and Characterization of Corn Starch and Lignosulfonate Blend Film with a High Content of Lignosulfonate

“…Furthermore, it has interesting properties, such as antimicrobial activity (Cruz et al 2001) and cytotoxicity (Ugartondo et al 2008) that render it potentially useful in high-value applications. The incorporation of lignin into starch matrix has a positive effect on its mechanical, thermal, and water and gas barrier properties (Lepifre et al 2004a;Lepifre et al 2004b;Calgeris et al 2012;Privas et al 2013;Kaewtatip and Thongmee 2013).…”